html{
  body{
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    width:100vw;
    height:100vh;
    box-sizing: border-box;
    .form{
      width:50vw;
      margin-bottom: 20px;
      display: flex;
      flex-direction: column;
      align-items: center;
      .row{
        display: flex;
        align-items:center;
        margin-bottom: 10px;
        .row-hd{
          width:4em;
        }
        .row-bd{
          width:20em;
          input{
            width:100%;
            height:100%;
          }
        }
      }
      .btn{
        width:10em;
        text-align: center;
        height:30px;
        line-height: 30px;
        border-radius: 5px;
        background-color: darkcyan;
        color:#fff;
      }
    }
  }
}